Issue 1. "Admin area. Log details page could not be opened if this log record was assigned to a guest customer". You can follow the next steps in order to manually apply the fix:
1. Open \Presentation\Nop.Web\Administration\Views\Log\View.cshtml file
2. Replace
@Html.ActionLink(Model.CustomerEmail, "Edit", "Customer", new { id = Model.CustomerId }, new { })
with
@Html.ActionLink(!String.IsNullOrEmpty(Model.CustomerEmail) ? Model.CustomerEmail : T("Admin.Customers.Guest").Text, "Edit", "Customer", new { id = Model.CustomerId }, new { })
P.S. Thanks to buzz for this quite fast issue report
Issue 2. "Mixed SSL content". See changeset 0df6444dd4ea for more info